PUL ID

PUL0321

PubMed

19233952, Appl Environ Microbiol. 2009 Apr;75(8):2284-93. doi: 10.1128/AEM.02621-08. Epub 2009 Feb 20.

Characterization method

enzyme activity assay, transposon mutagenesis

Genomic accession number

NC_007946.1

Nucelotide position range

1676979-1683154

Substrate

beta-glucoside

Loci

bgcAHIFER

Species

Escherichia coli/562

Degradation or Biosynthesis

degradation

Cluster number

1

Gene name

Gene position

Gene type

Found by CGCFinder?

- 1 - 1440 (-) CAZyme: GH1 Yes
- 1464 - 3137 (-) TC: gnl|TC-DB|P26218|1.B.3.1.3 Yes
- 3192 - 3503 (-) TC: gnl|TC-DB|U5MLJ3|4.A.3.2.9 Yes
- 3531 - 4853 (-) TC: gnl|TC-DB|C4X745|4.A.3.2.7 Yes
- 4968 - 5279 (-) TC: gnl|TC-DB|U5MIE1|4.A.3.2.9 Yes
- 5478 - 6176 (+) STP: STP|GntR No

PUL ID

PUL0321

PubMed

19233952, Appl Environ Microbiol. 2009 Apr;75(8):2284-93. doi: 10.1128/AEM.02621-08. Epub 2009 Feb 20.

Title

Characterization of a beta-glucoside operon (bgc) prevalent in septicemic and uropathogenic Escherichia coli strains.

Author

Neelakanta G, Sankar TS, Schnetz K

Abstract

Escherichia coli strains, in general, do not ferment cellobiose and aryl-beta-D-glucosidic sugars, although "cryptic" beta-d-glucoside systems have been characterized. Here we describe an additional cryptic operon (bgc) for the utilization of cellobiose and the aryl-beta-d-glucosides arbutin and salicin at low temperature. The bgc operon was identified by the characterization of beta-glucoside-positive mutants of an E. coli septicemia strain (i484) in which the well-studied bgl (aryl-beta-d-glucoside) operon was deleted. These bgc* mutants appeared after 5 days of incubation on salicin indicator plates at 28 degrees C. The bgc operon codes for proteins homologous to beta-glucoside/cellobiose-specific phosphoenolpyruvate-dependent phosphotransfer system permease subunits IIB (BgcE), IIC (BgcF), and IIA (BgcI); a porin (BgcH); and a phospho-beta-D-glucosidase (BgcA). Next to the bgc operon maps the divergent bgcR gene, which encodes a GntR-type transcriptional regulator. Expression of the bgc operon is dependent on the cyclic-AMP-dependent regulator protein CRP and positively controlled by BgcR. In the bgc* mutants, a single nucleotide exchange enhances the activity of the bgc promoter, rendering it BgcR independent. Typing of a representative collection of E. coli demonstrated the prevalence of bgc in strains of phylogenetic group B2, representing mainly extraintestinal pathogens, while it is rare among commensal E. coli strains. The bgc locus is also present in the closely related species Escherichia albertii. Further, bioinformatic analyses demonstrated that homologs of the bgc genes exist in the enterobacterial Klebsiella, Enterobacter, and Citrobacter spp. and also in gram-positive bacteria, indicative of horizontal gene transfer events.